A dual loop cooling system in a vehicle may include a low temperature coolant loop and a high temperature coolant loop. Typically, the low temperature coolant loop is designed to meet the cooling requirements of a charge air cooler, for cooling a condenser of an air conditioner of the vehicle, for transmission oil cooling, etc. The low temperature coolant loop may have adequate cooling capacity to cool the components at extreme temperature and/or operating conditions. The high temperature coolant loop may be an engine coolant system configured to decrease temperature of an engine block for maintaining the engine temperature for optimal engine functioning. The high temperature coolant loop may include a radiator, a water pump, coolant hoses, and other components.
The cooling capacity available in the high temperature coolant loop, especially during extreme temperature, may be limited. In one example, approach described in U.S. Pat. No. 6,941,245, this limitation of cooling capacity while cooling the engine may be handled by derating engine torque at extreme temperature and operating conditions.
However, the inventors herein have recognized potential issues with such systems. As one example, derating the engine torque to regulate engine temperature may compromise vehicle performance and diminish customer satisfaction.
The inventors herein propose systems and methods to address the above-described issues. In one example, a system includes a first coolant loop, a second coolant loop, separate from the first coolant loop, a heat exchanger configured to transfer heat between the first coolant loop and the second coolant loop, a bypass valve positioned between the first coolant loop to the heat exchanger, and a control valve positioned between the second coolant loop and the heat exchanger. The first coolant loop may be a low temperature coolant loop (for example, a liquid coolant loop for an air conditioner condenser) and the second coolant loop may be a high temperature coolant loop (for example, an engine coolant system). In one example, when additional cooling capacity is available in the first coolant loop, the bypass valve may direct coolant flow from the first coolant loop to the heat exchanger to transfer the additional cooling capacity to the heat exchanger. When additional cooling capacity is desired in the second coolant loop, the control valve may direct coolant flow between the heat exchanger and the second coolant loop to transfer the additional cooling capacity from the heat exchanger to the second coolant loop (e.g., to absorb heat from the second coolant loop).
In this way, a dual loop cooling system may transfer additional cooling capacity available in a low temperature loop to a high temperature loop through a heat exchanger or a thermal storage device without derating the engine, and thus maintaining optimal engine and vehicle operation. Additionally, use of a liquid coolant in the low temperature loop (instead of a refrigerant that needs a compressor), simplifies and reduces the cost and complexity of the dual loop cooling system.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.